Shiite mosques were the targets of three suicide bombings and a rocket strike, officials said, while another bomber targeted Iraqi security forces at a checkpoint.

Ashura is the commemoration of the death of Prophet Mohammad's grandson, Hussein, who was killed and entombed more than 1,300 years ago in Karbala.

Four civilians were killed in the crossfire of U.S. troops battling insurgents south of Baghdad. Seventeen civilians on their way to a holy site in Karbala were wounded.

Iraqi national security adviser Mowaffaq al-Rubaie said the attacks were intended "to try to draw a rift, to dig a wedge between the Shia and Sunnis in this country."

He said the insurgents were "trying to portray themselves as defending Islam against the infidels and the foreigners."

"They are blowing up pilgrims; they are blowing up people who are attending the mosque to do their Friday prayers."

The bloodiest attack killed at least 15 and wounded more than 24 during an Ashura holiday procession to al-Khadimain mosque, according to Iraqi police and U.S. military sources.

The bomber walked up to the group and detonated a suicide vest, a witness said.

In Iskandariya, about 25 miles south of Baghdad in Babil province, seven people inside a mosque for evening prayers were killed, and 10 people were wounded when a car bomb exploded just outside the building, Iraqi police said.

In the Iraqi capital's western sector, at least two suicide bombers attacked a Shiite mosque, wounding eight people, U.S. military officials said.

Iraqi guards identified the two suicide attackers and shot and killed one of the men, whose bomb exploded. The other man was blown up as he fled, the military said.

Iraqi police said two people were killed, but it was unclear if the bombers were included in the death toll.

In northwestern Baghdad, a rocket fired in the direction of the Husseiniyat al Thaqilan mosque killed one person and wounded three at a coffee shop, police said.

Two Iraqi security officers were killed and 19 people were wounded when a suicide bomber attacked a checkpoint in a Sunni neighborhood in northern Baghdad.

A car bomb attack also occurred at an Iraqi army checkpoint in Iskandariya, the U.S. military said. Three casualties -- no details were given -- were reported.

Attacks last year during Ashura killed more than 180 people in Baghdad and Karbalal.

Other developments

In southern Iraq, an American soldier on patrol was killed Friday by a roadside bomb, the U.S. military said.Two others were wounded when the homemade bomb detonated near a vehicle southeast of Camp Scania, outside Diwaniya. The death bring the number of U.S. troops killed in the Iraq war to 1,471.

The U.S. military also said two American soldiers were killed Thursday in separate attacks in northern Iraq.

Najaf police chief Ghalib al-Jazari said Friday his two sons were found dead outside Karbala after being kidnapped the day before.

An Indonesian TV company confirmed two journalists shown in a video being held at gunpoint by masked insurgents are 26-year-old Meutya Viada Hafid and 36-year-old Budiyanto. The two were last seen Tuesday in the Anbar province capital of Ramadi, where they were reportedly stopped by unidentified men in military uniforms.